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HubDoctor Pro Bearing Upgrade for Mavic Freehub - Any Experiences?

buckmulliganbuckmulligan Posts: 1,031
edited January 2019 in Workshop
At the weekend I decided to break open the toolbox and tackle an issue with my Mavic Ksyrium Elites that had been annoying me for a while. As a bit of background, I was experiencing a lot of cassette wobble from a worn nylon bushing in the freehub that was starting to cause the chain to skip occasionally under load as though the indexing was a little out; I'd serviced the whole drivetrain a few weeks ago trying to sort it out but to no avail, so bit the bullet and ordered the HubDoctor Pro Bearing Upgrade Kit on eBay from the US.

The kit basically replaces the white nylon bushing in the freehub with an aluminium adapter that houses a cartridge bearing, supposedly running with a lot less drag and requiring a lot less servicing:

815347d1373606315-mavic-freehub-rebuild-kit-hybrid-ceramic-bearings-mavic-hub.jpg

The aluminium adapter and cartridge bearing in the rear of the freehub needs some space back there, so the system ditches the rubber seal that usually sits behind the freehub and has a new one that seats around the edge of the aluminium adapter and seals against the edge of the hub body. The only problem with this is that this new seal design seems to create a hell of a lot of drag when freewheeling. When I install everything back on the bike without the seal in place, it's absolutely fantastic; I can spin the rear wheel up and several minutes later it's still coasting along quite happily! However when I put it all together with the seal in place, there's a ton of drag when freewheeling, the rear wheel tries to drive the pedals around and if you hold them still the rear derailleur cage lurches forward and there's a ton of chain sag. It was just about rideable when I reassembled it all but after leaving the bike standing for a few hours the freehub drag got a hell of a lot worse and was basically unrideable with the seal in place. I'm 99% sure it's all assembled correctly, because it's absolutely fine without the seal in place, but obviously I'm not so keen on running it like this for any prolonged period of time. Is it possible that the lube that I've used inside the freehub and on this seal has caused the rubber to swell and exacerbate this drag?

Any help or experiences with this kit are much appreciated!

TL;DR - has anyone used this system? If so, does it run completely drag free and what lube are you using in the freehub body and for the rubber seal?

Posts

  • ugo.santaluciaugo.santalucia Posts: 26,589
    Neat solution, I like it!
  • MikeBrewMikeBrew Posts: 814
    Bought one a couple of years ago....Excellent ! Lube-wise, Pedro's GO! or Shimano hydraulic mineral oil..
    http://pedros.com/faqs/which-lubricant- ... c-freehub/ Whatever you use needs to be low viscosity.
  • buckmulliganbuckmulligan Posts: 1,031
    Neat solution, I like it!

    Yeah, I thought so too. It's expensive but hopefully the magical combo of better performance and less maintenance. It's certainly cured the play I had in the freehub, so that's one issue solved but replaced by another at the moment!
    MikeBrew wrote:
    Bought one a couple of years ago....Excellent ! Lube-wise, Pedro's GO! or Shimano hydraulic mineral oil. Whatever you use needs to be low viscosity.

    Thanks, that's useful info. Shimano Mineral Oil was going to be my next port of call, but thought I'd canvass some opinion first! I've used it in the freehub before but thought it was slightly too light to keep that nylon bushing well lubed so went for something slightly thicker. Now that's no longer an issue I'm thinking of giving it another shot. How has your's held up since installing it?
  • MikeBrewMikeBrew Posts: 814
    It's still going strong two years on, and has eradicated cassette rock altogether. Thing is, the hub body lasts forever and the nylon bearing wears out in no time at all. The mod makes perfect sense.
  • buckmulliganbuckmulligan Posts: 1,031
    MikeBrew wrote:
    It's still going strong two years on, and has eradicated cassette rock altogether. Thing is, the hub body lasts forever and the nylon bearing wears out in no time at all. The mod makes perfect sense.

    Glad to hear it!

    As a quick update, I contacted the vendor enquiring about recommended lubes and he said that he'd ship out some extra seals and see if it cures the issue. Great service considering he's across the atlantic.

    Fingers crossed!
  • ugo.santaluciaugo.santalucia Posts: 26,589
    Rubber seals can cause a bit of drag, until they settle, as long as you don't have chain-slap it's a non issue... it will improve with mileage
  • navrig2navrig2 Posts: 1,667
    I have just finished a Hub Doctor repair to my Mavic Kyserium wheels.

    My experience has been reasonably good. It took tow goes to get it right.

    The first attempt when smoothly and following the instructions was dead easy.

    https://photos.app.goo.gl/3H8fzwvWpqauPnPf7

    I thought I had sanded the hub enough when I could squeeze the freehub back on however after assembly there was still a lot of drag. I tried to go for a ride but because there was so much drag there was a lot of slack chain and it looked to me that freewheeling with a lean to the left could have resulted in the spokes and chain clashing.

    Searching the web suggested that running in the repair would reduce the drag and that the drag was related to the seal installed on the inside face of the freehub. However the only way to run it in was to ride it and let it freewheel!

    I messaged Doctor Hub asking for his thoughts. He suggested a 2nd washer or that I had not sanded the hub enough.

    I dismantled the hub again and spent a few more minutes sanding the hub until the freehub slipped on more easily. I then rebuilt and tested it on an upside down bike. It freewheels quite nicely although there is a rough spot. I've put it onto the turbo and will give it a run (although not a lot of freewheeling) this week.

    Tips:

    If you can get the right sealed bearings I am not sure you need the Hub Doctor kit. At £50+ from the USA it's expensive for 2 bearings, some sandpaper and a basic tool which helps keep the sanding consistent around the hub.

    If you do buy the kit you will need more sandpaper or, even better, emery cloth.

    The Hub Doctor tool is useful but doesn't seem to be be critical. Patience and care will get the same result.

    Don't drop the spring out of the pawls. They are small and finding one in a busy, poorly lit garage is a nightmare.
  • keef66keef66 Posts: 13,123
    Do Mavic still make hubs / wheels using this glaring design flaw? (and fail to sell a reasonably priced replacement part) It's not as if a Ksyrium Elite is sold as a cheap and cheerful disposable wheelset is it?
  • navrig2navrig2 Posts: 1,667
    keef66 wrote:
    Do Mavic still make hubs / wheels using this glaring design flaw? (and fail to sell a reasonably priced replacement part) It's not as if a Ksyrium Elite is sold as a cheap and cheerful disposable wheelset is it?

    Mine were 7 years old so well beyond warranty. I think the design remains the same.
  • Vino'sGhostVino'sGhost Posts: 4,129
    +1 for the thinner oil use.

    I use a light gun oil, just because i had some and it works brilliantly. Because it doesn't say bike on the tin its not expensive either.
  • buckmulliganbuckmulligan Posts: 1,031
    Navrig2 wrote:
    If you can get the right sealed bearings I am not sure you need the Hub Doctor kit. At £50+ from the USA it's expensive for 2 bearings, some sandpaper and a basic tool which helps keep the sanding consistent around the hub

    It's hard to tell from all of those drawings, but doesn't your kit use the aluminium bearing adaptor that presses into the back of the freehub? This is the critical, custom-machined part that costs the money, not the bearings.
  • Did this on two sets now. Still cant believe after so many years they are still using that censored design!

    First time I used the hubdoctor set was in 2012 and again in 2017. Both still going strong. A worthy upgrade.
  • I'm a bit late into this thread but i have the identical problem with the Mavic hub. I fitted a new hub with little difference in reducing the lateral cassette movement. The plastic bushing is basically in-built obsolescence or at best stretch of the imagination - saving weight - the plastic bushing is about 3g and a cartridge bearing about 20g. A slightly redesigned set up could have a cartridge bearing fitted with a tremendous reduction in wear on the other bearings and ultimately, the chain and cassette and stop any lateral movement. The HubDoctor adapter/flanged bush allows for a standard bearing to be fitted - i searched Simply Bearings and they do not stock a standard cartridge bearing or flanged type of suitable size for the hub. The bushing is very thin which is why the flanged bush adaptor is needed. The aluminium Hubdoctor flange could easily be made by a half decent engineer on a lathe but then you would need to source the bearings and the rubber seal (not sure about getting this included in Dragons Den just yet!). I've emailed Simply Bearings for help but for now, i'll be relying on the HubDoctor to help me out!
    To cap it all Mavic are apparently redesigning their hubs, bit late for most of us though!
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